1. Field of the Invention
The present invention relates to an apparatus for removing film from a film magazine by disengaging the film from a film engagement claw provided on a spool of the film magazine.
2. Description of the Related Art
Conventionally, photographic film is wound on a spool in a film magazine. The film is engaged with the spool through the engagement between a hole formed in the tail end of the film and a claw or hook provided on the spool. This ensures proper feeding of the film when the film magazine is placed in a camera for taking pictures. To remove the film from the film magazine for development, the film needs to be released from the spool.
Each film magazine is provided with a mechanism for feeding out the leading end of the film. As the spool is turned in a film unwinding direction, the leading end of the film comes out of a film slot of the film magazine. The film is then taken up into a light-shielded magazine in a dark box. In order to release the film from the spool, an operator breaks the film magazine and disengages the hole formed in the tail end of the film from the engagement claw of the spool, or cuts the film near the tail end thereof which is fixed to the spool of the film magazine.
Various apparatuses have been proposed which automatically take up film utilizing a film magazine which has a film engaging means from which the film is easily disengaged. Examples of such apparatus will be described below.
Japanese Patent Application Laid-open No. 5-232633 entitled "Film Unwinding Apparatus" discloses a film magazine in which hooks project from the body of a spool in the film winding direction. Film is wound on the spool with a hole in the tail end of the film engaged with hooks. The operation of the film unwinding apparatus will now be described with reference to FIG. 1 (PRIOR ART) and FIG. 2 (PRIOR ART).
FIG. 1 (PRIOR ART) is a top view showing a conventional film take-up apparatus in which the above-described film unwinding apparatus is used, and FIG. 2 (PRIOR ART) is a cross-sectional view of the film take-up apparatus. A film unwinding apparatus 21 has a spool driving motor 23 which drives a spool driving shaft 27 through a belt 25, a roller driving motor 29 which drives a film driving roller 22 through a belt 20, and film guide tracks 24, 26. A pressure roller 28 is brought into contact with the film driving roller 22 by a spring force. A flywheel 6 is mounted on the spool driving shaft 27.
A film magazine 1 is set such that a spool core 7 is coaxial with the spool driving shaft 27, and a light-shielding tongue 5 is opened. When the roller driving motor 29 and the spool driving motor 23 are energized, the film driving roller 22 revolving at a high speed and the spool core 7 revolving at a low speed in an unwinding direction cause the leader portion 9 of the film to come out of a cassette shell 3.
A leading end 10 of the film is fed between the film driving roller 22 and the pressure roller 28 and between the film guide tracks 24, 26. When a film sensor 2 detects the leading end 10, the spool driving motor 23 is turned off. The roller driving motor 29 continues revolving the film driving roller 22 to feed the film into a portable collector bin 4. This causes the spool core 7 and the spool driving shaft 27 with the flywheel 6 to revolve. When the tail end of the film is reached, the inertia of the flywheel 6 causes the spool core to keep revolving, thereby disengaging long hooks from holes 14 formed in the tail end 12 of the film. The film driving roller 22 pulls out the tail end 12 to thereby remove the film from the cassette shell 3.
Japanese Patent Application Laid-open No. 4-122925 entitled "Photographic Film Magazine" discloses a film magazine having a spool provided with a movable claw with which a hole in the tail end of film is engageable. A claw moving member is provided in an interlocking relation with the movable claw. The claw moving member is operated using a tool or directly by hand. Alternatively, a Jig or the like is inserted inside the film magazine through a film slot, thereby disengaging the claw of the spool from the hole formed in the tail end of the film. Such a film magazine is used together with a film take-up apparatus which is provided with a mechanism for operating the claw moving member or which is provided with a jig for releasing film and a mechanism for inserting the jig into the film magazine.
In the case where a claw moving member is provided outside a film magazine near a spool core, the claw moving member is operated using a movable shaft, or directly operated without using a tool or jig. In the case where a claw moving member is provided inside a spool shaft, the claw moving member is operated by inserting a sheet-like tool or jig into a film magazine. Also disclosed is a film magazine in which a claw moving member is integrally formed with a movable claw. In this case, a jig is inserted into a film magazine to directly disengage film from the claw.
FIG. 3 (PRIOR ART) is a perspective schematic view showing an example of such a conventional film take-up apparatus. In the film take-up apparatus, a film magazine 30 is placed in a film magazine case 31, and then a jig 32 is inserted into a film slot 33. The jig 32 comprises two sheet-like elastic members between which photographic film 34 passes and has a cut-out portion for disengaging an engagement hole from an engagement claw. As a spool is revolved in a film unwinding direction, the leading end of the film comes out from the film slot 33 while being guided by the jig 32.
A driving motor 36 is turned on to rotate a film transport driving roll 39 to thereby transport the leading end of the film from the film slot 33 to a film transport track 35. Furthermore, a driving motor 37 is turned on to rotate a film transport driving roll 38 to thereby advance the film. Finally, the jig 32 is inserted to the position of the engagement claw of the spool to release the film 34 from the claw, thus freeing the film 34 from the spool. This allows the film 34 to be unwound as far as its tail end.
As has been described above, film is taken up either manually or using a film take-up apparatus. The manual method is simpler, but requires a film magazine to be broken or film to be cut away in order to free the film from a film engagement claw.
A film magazine is sturdy, and its components are tightly joined together to shut off light. As a result, it is difficult to break the film magazine. In the case of cutting film, because of the tail end of the film being left in a film magazine, it is difficult to reuse the film magazine, as in the case of breaking the film magazine. Also, it is difficult to rewind the film with its tail end cut off back into a film magazine because the film has lost a hole formed in the tail end of the film.
On the other hand, the film take-up apparatuses disclosed in Japanese Patent Application Laid-open Nos. 5-232633 entitled "Film Unwinding Apparatus" and 4-122925 entitled "Photographic Film Cassette" allow the tail end of film to be easily freed from a film engagement claw of a spool for film take-up without cutting the film or breaking a film magazine.
However, due to a complex structure including a plurality of motors for rotating a spool and for transporting film, a film releasing jig, a jig driving unit and the like, the apparatuses become large.
Also, large apparatuses with a complex structure involve higher costs and rather complicated operation and maintenance. Such film take-up apparatuses are suitable for use in large-scale processing laboratories but are not suitable for use in small-scale processing laboratories or for personal processing use. Cutting film or breaking a film magazine is still in popular use.